Benjamin i



B. l. JOHNSON.

SPARK PLUG.

APPLlcAUoN FILED ocT. 31, 1918.

' 1,312,850. Patented Aug. l2, 191).

F @inve-14190@ BENJAMIN I. JOHNSON, 0F G /iscoruliL dGBTH nAKoTA.

sgfllittion of Letters Patent.

Application med october ai, 1918.

T 0 all whom it may concern;

Be it known that L BENJAMIN I. JoHN- son, a citizen of the United States, residing at Gascoyne, in thecounty of Bowman, State of North Dakota, have invented a new and useful Spark-Plug; and I do hereby declare the follmving to be a full, clear, and exact description of the invention, such as will elk able others skilled in the art to which it appertains to make and use the ,saine` i This invention relates to an improved spark pluzgr particularly designed for use in connection w ith internal combustion engines, for igniting the charge.

One of the objects of the invention is to provide an improved spark plug having fm eltrode constructed from a high stenciled strength steel.

A further object of the invention is to provide the lower end of the electrode with f a metallic nut constructed of any suitable non-corrosive metal referably brass provided with a terminalpto cooperate with an adjacent sparking terminal, so as to create a jump spark from one to the other.

A further object of the invention is to provide a small copper washer for the lowerl 'end of the electrode.

A further object of the invention is to pro .vide a copper washerasbostos Covered for the upper end of a porcelain filler of the lower end of the spark .plug casing.

A further object ot' the invention is the provislm Of an upper wood fiber holder and a lowerporcelain holder for the electrode, there beingr an insulation of miea partially telescoping the adjacent ends of the wood fiber holder and porcelain holder.

A further object ot' the invention is the provision of" means 'for holding the elec trode in diderent adjusted positions.

A further object of the invention is to provide a casing, having means on its interior, for limiting or holding the holders for the electrode in spaced relations to each other.

In practical fields the details of construe-- tion may necessitate alterations falling within the scope of what is ciaimed.

The invention comprises further features and combination of parts as hereinafter set forth shown in the drawings and claimed. A

Figure 1 is a View in sido elevation of the spark plug.

Patented Aug. 12, 1919.

seriai No. 250,474.

Fig. 2 is a vertical sectional idew of the same. A Fig. 3 is a plan View of the spark plug.

F 1g. l is a sectional view on line 4-4 of Fig. 2.

Referring more especially to the drawings 1 l designates a casing of the spark plug, which is ext-eriorly threaded as shown at 2, so as to bethreaded into the end of theI cylinder casing. The interior of the casing is provided with annular shoulders 3 and i, and mounted in the casing 1 are electrode holders 5 and (i. The holder 5 isconstructed of wood iberx and its reduced portion 6 telescopes into the casing l, so that the shoulder T may engage the marginal edge of the flange 8. The holder 5 has a second rcduced part 9, engaging the main portion of the bore 10 of said casing, so that theshoulder 11 intermediate the portions 6 and 9 may engage the shoulder 3. The electrode 12, which may be constructed of any Suitable material preferably soft copper or the like is mmlltofl in the bore 13 of the holder 5. T119; lower end of the bore 13 of the holder 5 ii'cs outwardly as shown at 14. The holder 6. has a reduced portion 15 fitting the main portion of th'e bore 10 of the casing 1. The holder 6 has a shoulder 16 and interposed between the shoulders Je and 16 is a suitable washer 17 constructed of any suitableinaterial preferably copper and covered with asbestos. "he upper part of the bore 18 or the holder (i (which is constructed of any suitable material preferably porcelain) 'larcs outwardly as shown at 19. Surround ing the electrode 12 is a filler 20 constructed ot any suitable insulating material preitei.p0 ably mica. This filler is tapered toward both ends, so as to fit as shown into the out- S wardly {iared portions 11i and 19 of the bores 13 and 18 respectively. The holder 6 at the lower end of the bore 18 has countersunk therein a tubular washer or sleeve 21 constructed of any suitable material ably oit' copper. The lower end of the elec-4 trode has an enlargement 22 contacting with the sleeve 21, and the sleeve 2i being countersuulr into the holder ii. 'the holder is supported in the easing 1.

.i rejecting from the lower portion of the, casing 1 is a sparking;l

v terminal S55-L andl denotes a eurred terminal carried by the enlargement 252. The terminal 2l extends toward the ternunal 23 and both terminals are dwfrfned to be platinum prefery vwhich nuts a lead or wire, from a suitable `timer Or commutator (not shown) may be connected. A washer 27 is mounted On the electrode in Contact with the holder 5, and

interposed between the nut and the washer 27 is a split Washer 28, the ende of which are oil'set from each other, and by tightening up on the nut 25, steady pressure is yieldably exerted to hold the shoulders 3 and ll in Contact, and the washer 17 between the shoulders 4 and 16.

The invention having been set forth what is claimed as new and useful is In combination with a spark plug casing having interior concentric shoulders, of inner and outer porcelain and fiber holders telescoping said casing and engaging said shoulders, said holders having axially alined bores having their adjacent ends flared outwardly a copper sleeve eountersunk in the lower end of the lower holder, an electrode of soft copper extendingr through the holders and having an enlargement contacting with the copper sleeve, and means on the upper part of the electrode for drawing,` the aforesaid parts together, a washer between a shoulder or' the lower holder and one of the `shoulders of the casing, a filler surrounding the electrode and having its Opposite ends telescoping into the flared out portions of the holders, the lower part of thc casing and the enlargement of the electrode having coperating sparking terminals.

In testimony whereof I have signed my name to this spccification'n the presence of two subscribing witnesses.

BENJAMIN 1. JOHNSON.

Witnesses FRANK H. ERICKSON, JOHN N. THEN. 

